Hydraulic fast locking and loosening device for bearing assemblies of rolling-mill cylinders, and corresponding method of use

ABSTRACT

A hydraulic locking and loosening device ( 40 ) is set on the neck of a rolling-mill roll or back-up roll with a conical part ( 3 ) and a cylindrical part ( 4 ), and comprising an oil-film bearing ( 7, 8 ), a spacer ring ( 16 ), a thrust bearing ( 15 ), a thrust ring ( 17 ), and a threaded lock ring ( 18 ). The locking device ( 30 ) comprises a body ( 21 ) inserted at the centre in a ram ( 22 ) to form a hydraulic actuator with two annular chambers ( 23 ), longitudinal arms ( 31 ), on each of which is provided a C-shaped notch ( 32 ), and cover ( 24 ) for closing the hydraulic chambers ( 23 ). A variant of the hydraulic locking and loosening device ( 40 ) is provided with a bayonet device for its engaging on the roll end.

This application claims priority to International Patent ApplicationSerial No. PCT/EP02/09785 filed on 2 Sep. 2002, claiming priority toItalian Patent Application Serial No. MI12001A001859 filed on 4 Sep.2001.

FIELD OF THE INVENTION

The present invention relates to a hydraulic fast locking and looseningdevice, which can be temporarily mounted on bearing assemblies thatsupport in rotation the necks of rolls of rolling-mill, for tighteningand loosening the chock of the roll neck, as well as to a method for useof said device.

STATE OF THE ART

In roll stands, and more in particular in back-up rolls, it is commonpractice to utilise hydraulically actuated or screw-actuated devices foraxially locking rolling mill bearing assemblies in their positions onthe roll necks.

In known rolling mills, such locking devices are designed as integralparts of the bearing assemblies, thereby increasing considerably thecost of said assemblies.

A further drawback of screw actuated locking devices is that they aredifficult to tighten, frequently requiring the use of cables pulled bymeans of overhead cranes. This process increases the risks of injury forthe maintenance staff and possible damage to the equipment.

Another known technique is to use hydraulically actuated portable toolsthat can be temporarily mounted on the bearing assemblies of the rollingmills however, such tools are designed for tightening the bearingassemblies on the roll necks, and are not useful for loosening saidbearing assemblies. Thus, disassembly is carried out with other means,which in all cases comprise the use of overhead cranes and/or of otherhydraulically or mechanically operated means.

SUMMARY OF THE INVENTION

Consequently, the purpose of the present invention is to overcome theproblems discussed above of known state-of-the-art fast locking andloosening devices, by providing a hydraulic locking and loosening deviceadapted for locking and loosening bearing assemblies on roll necks ofrolling mills, which is easy to operate and saves both time and workduring use.

Another purpose of the present invention is to provide a hydrauliclocking and loosening device which ensures economy of operation, reducesmaintenance, and enables an inexpensive conversion of previous morecomplex mechanical and hydraulic locking systems.

Another purpose of the invention is to provide a hydraulic locking andloosening device designed to operate on roll ends with end sections thatare shorter and of a simpler structure.

It is also an object of the present invention the provision of ahydraulic device for locking and loosening of bearing assemblies whichis reliable and compact.

The above purposes are achieved by a hydraulic locking and looseningdevice having the features of claim 5. The inventive configuration ofthe device comprises a smaller number of components and can beassociated to a roll bearing assembly of a particularly simplestructure. The reduction in costs that derives therefrom forrolling-mill plants is consequently substantial. The structuralsimplicity of the device renders it easy to use and repair. Since it iseasy to remove from its seat on the mill bearing assembly, one hydrauliclocking and loosening device can be used on a plurality of roll stands.

According to a particular aspect of the present invention, there ismoreover provided a method for the use of the hydraulic locking andloosening device for roll bearing assemblies, the said method having thefeatures specified in claim 11.

According to yet another particular aspect of the present invention,there is also provided a hydraulic locking and loosening device for rollbearing assemblies having the features specified in claim 1.

The proposed bearing assembly has a simplified structure and can replaceother bearing assemblies of a more complex structure. It is structurallyfaster and simpler to build and moreover involves a chock end plate forthe reinforcement that is of a simpler form, as well as a cover that isalso simpler.

BRIEF DESCRIPTION OF THE FIGURES

Further characteristics and advantages of the invention will become moreapparent in the light of the ensuing detailed description of preferred,but not limitative, embodiments of a hydraulic device for locking andloosening of bearing assemblies of roll stands and of the correspondingmethod of use, illustrated by way of non-limiting example by means ofthe accompanying drawings, in which:

FIG. 1 shows a partial longitudinal sectional view of a bearing assemblyon which a hydraulic locking and loosening device according to theinvention is employed;

FIG. 2 shows a side view of the hydraulic locking and loosening deviceof the invention;

FIG. 3 shows a view from the rear of the device of FIG. 2;

FIG. 4 shows a front view of the device of FIG. 2;

FIG. 5 shows a sectional view of the device illustrated in FIG. 2,mounted on a bearing assembly in operation;

FIG. 6 shows a side view of the device of FIG. 2 installed on a bearingassembly in operation;

FIG. 7 shows a longitudinal section of another embodiment of a hydrauliclocking and loosening device according to the invention, installed on acorresponding bearing assembly in operation,

FIG. 8 represents a section, along the line A-A, of the device of FIG.7; and

FIG. 9 represents a side view of the hydraulic device of FIG. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

With reference to FIG. 1, the end of the roll 1, in particular of aback-up roll, is represented, with a hydraulic locking and looseningdevice according to the present invention, globally indicated by thereference numeral 2. The roll end portion has a first tapered part 3,advantageously of a conical shape, and a second cylindrical part 4, bothparts being supported in rotation in a housing of the frame 5 of theroll mill. On the side of the roll of larger diameter, there is provideda seal 6 to retain oil of the oil-film bearing. The latter comprises abushing 7 made of white metal alloy and a sleeve 8 with tapered innersurface to adapt to the tapered portion 3 of the roll. The bushing 7 isprovided with apertures for oil feed 9 and is fixed on the frame 5 bymeans of lock pins 10, whilst the sleeve is in turn fixed, in order toprevent rotation, on the roll neck by means of the ring keys 11 and 12.In a position corresponding to the end part of the bearing assemblythere is provided chock end plate 13, which is fixed on the frame 5 bymeans of screws and is closed on the external side by a flange 14.Around the cylindrical part 4 of the roll neck there is fitted a thrustbearing 15, held inside a corresponding hole of the chock end plate 13.The thrust bearing 15 is held firm between a ring 16 on the inside ofthe neck of the cylinder and a thrust ring 17 on the outside. The thrustring 17 is secured to the cylindrical part 4 of the roll, to preventaxial displacement, by a threaded lock ring 18, screwed on a two-partthreaded ring 19 and fastened in a groove of the cylindrical part 4. Twolocking keys 20 ensure locking of the ring 18 to prevent any looseningduring the operation of the roll mill.

With particular reference to a first embodiment of the invention, in thepartial section above the axis of the bearing assembly, with referenceto FIG. 1, the hydraulic locking and loosening device, globallydesignated by the reference numeral 30, is installed on the bearingassembly for carrying out the locking operation, and comprises acylindrical body 21, surrounded by a ram 22. Both the body 21 and theram 22 are made in such a way as to form between them two chambers ofannular shape and to form a double-acting hydraulic actuator 23. Aprotective end cap 24 closes the hydraulic outer chamber of the actuator23 formed in the space between the body 22 and the ram 21. The device 30is fixed to the back-up roll body during the locking and looseningoperation by means of a fixing screw 26. A quick-release coupling 27enables connection to a hydraulic power source for actuating the device30. The hydraulic locking device 30 is provided with two pin engagementlevers 28 for facilitating twist-lock insertion on the back-up roll end.Four locking pins 29 are set on the thrust ring 17 and fix the hydraulicdevice 30 to the bearing assembly during operation. The device ram 22 isprovided with four arms 31, each of which has a seat or notch 32 toengage the respective locking pin 29. The engaged position of thehydraulic locking and loosening device is illustrated more clearly inFIGS. 5 and 6.

Operation of the hydraulic device 30 is described in what follows.Whenever it is necessary to install the oil-film bearing 7, 8 and thethrust bearing 15, the various elements of the bearing assembly arefitted around the end part of the roll 1. First the bushing 7 is fitted,then the sleeve 8 and the ring 16, and next the thrust bearing 15 andthe thrust ring 17. The chock end plate is closed by the flange 14, thethreaded ring 19 is tightened on the roll end part and the lock ring 18is fitted on the ring 19.

The device 30 is mounted temporarily and releasably, for carrying outthe operation, on the end part of the roll 1. The device ram 22 isturned through 45° about its own axis with the aid of the levers 28 toengage, with the four arms 31, the pins 29 by means of the C-shapedseats or notches 32 for blocking the device, which is further fastenedon the end of the cylinder by a screw 26, which is screwed on the endpart of the cylinder. The locking device is then pressurisedhydraulically by means of the actuator 23, which exerts an axial forcedirected towards the left in FIG. 1, forcing the thrust ring 17 againstthe thrust bearing 15 and pushing the entire chock and the oil-filmbearing assembly against the tapered part 3 of the roll neck. The lockring 18 is then tightened against the thrust ring 17, for example bymeans of a special C-shaped spanner. Two locking keys 20 are fitted inroll end key-ways and screwed to the lock ring 18.

The pressure is then removed from the assembly device 30, and the latteris then detached from the roll end, first by turning the arms 31 throughan angle of 45°, and then by unscrewing the device blocking screw 26.

The process of disassembly of the chock and of the bearing assemblyusing the same hydraulic locking and loosening device 30 is the reverseof the operation described above: the tool is used to pull the thrustring 17 away from the chock end plate 14 and to loosen the sleeve 8.

With particular reference to a second embodiment of the invention,illustrated in FIG. 7 and following figures, the hydraulic locking andloosening device, globally indicated by reference numeral 40, isinstalled on the bearing assembly for locking operation, and comprises acylindrical body 41 surrounded by a ram 42. The body 41 and the ram 42are designed in such a way as to provide two chambers of an annularshape, which constitute a double-acting hydraulic actuator 43. An endcap 44 closes the external hydraulic chamber of the actuator 43 formedby the space between the body 42 and the ram 41.

The device 40 is fixed to the back-up roll body during the locking orloosening operation by a first twist-lock bayonet fast-block coupling.The first twist-lock bayonet device comprises a certain number of teeth46 set on the body 41, which are adapted to engage in the annular groove47 present on the end part of the roll 1. The first bayonet device isoperated by aligning the teeth 46 with the splines on the roll end,axially translating the device or tool 40 until the teeth 46 are set onthe annular groove 47 and turning it through a given angle, for example45°. The tool is thus fixed to the roll end.

The hydraulic locking device 40 is provided with two levers 48′, 48″used for tool control and for generating the rotary movement necessaryfor fixing the bayonet device on the roll end.

A second twist-lock device is provided for fitting the tool 40 on thethrust ring 57. The longitudinal splines present on the thrust ring 57enable the teeth 52 of the end of the arms 51′, 51″ to translate axiallyand insert in the annular groove 53 of the thrust ring 57. When the tool40 is turned through the same pre-defined angle, as mentioned above, thedevice 40 comes to be fixed to the bearing assembly for carrying out theoperation. The device 40 can have a different number of arms 51, forexample three or four, according to the structural needs, and the numberof the corresponding splines is defined accordingly.

A quick-release coupling enables coupling of the hydraulic actuator 43to a hydraulic pump for engaging the bayonet arrangement 52, 53 to theend of the cylinder 1 when the hydraulic pressure is applied in theinner annular chamber and for disengaging when the hydraulic pressure isapplied in the outer annular chamber.

A suspension arm 58 is advantageously provided for gripping the toolwith a lifting device (not illustrated in the figures). This armfacilitates manipulation of the tool during operation, or else forstoring.

The operation of the device 40, when it is used for the locking of thebearing, is as described in what follows. Whenever it is necessary tofix the oil-film bearing 7 and the thrust bearing 15, the variouselements of the bearing assembly are fitted around the end part of theroll 1. The bushing 7 is fitted first, followed by the sleeve 8 and thering 16, and finally by the thrust bearing 15 and the thrust ring 17.The chock end plate is closed by the flange 14, and next the ring 19with a thread on its outer surface is shifted onto the roll end andfinally the lock ring 18 is screwed onto the ring 19.

The device 40 is installed, temporarily and releasably for carrying outthe operation, at the end of the roll 1. The device is then turned aboutits own axis through an angle of, for example, 45°, using the levers 48for engaging the first twist-lock bayonet device with the roll end andthe second twist-lock bayonet with the thrust ring 57.

The assembly device 40 is then supplied with hydraulic fluid underpressure by means of the actuator 43, which exerts an axial forcedirected towards the left of FIG. 7, forcing the thrust ring 57 againstthe thrust bearing 15 and pushing the entire reinforcement and theoil-film bearing in close contact against the tapered part of the rollneck (not illustrated in detail in this figure). The lock ring 18 isthen tightened against the thrust ring 57, for example by means of aspecial C-shaped spanner. If necessary, locking keys are inserted inkeyways at the roll end and screwed to the lock ring 18.

The pressure is then removed from the locking device 40, and the latteris detached from the end of the cylinder by turning the bayonet devicesthrough an angle of approximately 45° and then axially sliding thelocking device away from the roll end.

The process for loosening and removing the chock and the bearingassembly using the same locking and loosening device 40 is the reverseof the one described above, in which the same tool is used for pullingaway the thrust ring 57 from the chock end plate 14.

From what has been said above it is evident that the locking andloosening device according to the invention achieves all the objectivesset above. Its design enables savings in terms of time and resources ascompared with locking and loosening tools of the prior art because thedevice is not permanently connected to one cylinder only, and thestructures of the roll end section, of the chock end plate and of thecover are simplified. Thanks to its simplified design and to the factthat it has only a few moving parts with standard seals and connectors,the device according to the invention requires limited maintenance. Itis moreover easy to use since only three main operations are necessaryto tighten a bearing assembly.

1. A roll bearing assembly comprising a roll with an end neck having afirst portion, with a tapered external surface, and a second portion, atthe external end of the roll neck, with a cylindrical external surfaceand adjacent to said first portion, and further comprising, from theinternal end to the external end of the roll neck, an oil-film bearingfitted on said first portion, a spacer ring, a thrust bearing fitted onthe second portion of the roll neck and contacting the spacer ring, athrust ring fitted on the second portion of the roll neck and contactingthe thrust bearing and a threaded lock ring fitted on said secondportion of the roll neck and contacting the thrust ring, said thrustring being provided with first engagement means on its outer surface forreleasably engaging a roll bearing locking and loosening device forlocking and loosening operations; wherein said first engagement means issuitable to be connected solidarily to a corresponding second engagementmeans provided on longitudinal arms of a locking and loosening device,such that said first and second engagement means are reciprocallyengaged for fixing a hydraulic device to the roll bearing assembly inthe course of both locking and loosening operations.
 2. Roll bearingassembly according to claim 1, wherein the first engagement meanscomprises at least two pins fixed radially on the external surface ofthe thrust ring to engage second engagement means comprisingcomplementary C-shaped indentations of a roll bearing locking andloosening device.
 3. Roll bearing assembly according to claim 1, whereinthe first engagement means comprises an annular groove on the thrustring, said annular groove configured to engage with second engagementmeans comprising complementary teeth of a roll bearing locking andloosening device.
 4. Roll bearing assembly according to claim 1, whereinthere is provided a chock end plate with a housing designed to receivethe external part of said thrust bearing.
 5. A roll bearing assemblyaccording to claim 1 wherein said locking and loosening device is anhydraulic locking and loosening device comprising a substantiallycylindrical body, a cylindrical ram provided with a central hole adaptedto be set around said cylindrical body at a first ram end side, such asto form at least two annular hydraulic chambers in correspondence of thesurface of reciprocal contact, a cylindrical end cap to close at leastone of said hydraulic chambers, and at least two longitudinal armsextending in an axial direction towards a second ram end side, each ofsaid longitudinal arms being provided with releasable second engagementmeans to releasably engage a roll bearing assembly for locking andloosening operations; wherein the second engagement means are suitableto be connected solidarity to the corresponding first engagement meansprovided on the thrust ring of the roll bearing assembly, such that thefirst and second engagement means are reciprocally engaged for lockingsaid hydraulic device to the roll bearing assembly in the course of bothlocking and loosening operations.
 6. Roll bearing assembly according toclaim 5, wherein said releasable engagement means comprise a C-shapedindentation on said longitudinal arms.
 7. Roll bearing assemblyaccording to claim 6, in which the cylindrical ram is provided with fourlongitudinal arms.
 8. Roll bearing assembly according to claim 7,wherein there is provided a screw, set axially, for fixing said deviceto one roll end during operation.
 9. Roll bearing assembly according toclaim 5, wherein said releasable engagement means comprise bayonetdevices, of the twist-lock type.
 10. Roll bearing assembly according toclaim 9, wherein one of said bayonet devices of the twist-lock type isset on said longitudinal arms, and the second is set on said cylindricalbody.
 11. A method for locking bearing assemblies on a roll end by meansof a hydraulic device according to claim 5, comprising the followingsteps: a) fitting in the following order a bushing, a tapered sleeve, aspacer ring, a thrust bearing, and a thrust ring on the neck of a roll;b) closing a chock end plate by means of a flange; c) fitting of athreaded ring on the roll end part and of a lock ring around said ring;d) assembling the hydraulic device around the end part of said roll; e)rotating the hydraulic device about its own axis by an appropriateangle, to engage operatively first engagement means located on saidthrust ring, with second engagement means located on said hydraulicdevice so as to reciprocally lock the hydraulic device and the thrustring; f) fixing said hydraulic device to the end of the cylinder byactuating fixing means on the end of the cylinder; g) pressurizing thehydraulic device by means of an actuator, so as to exert an axial forceand to force said thrust ring against said thrust bearing and to pushthe chock and the oil-film bearing against said roll neck; h) tighteningsaid lock ring to the thrust ring; i) releasing the pressure from saidhydraulic device; j) rotating the device by an appropriate angle; and k)removing said fixing means and extracting the hydraulic device.
 12. Amethod for loosening of bearing assemblies from a roll end by means of ahydraulic device according to claim 5, comprising the following steps:a) assembling the hydraulic device on the end part of said roll; b)rotating the device about its own axis through an appropriate angle, toengage operatively first engagement means located on said thrust ring,with second engagement means located on said hydraulic device thusreciprocally locking the device and the thrust ring; c) fixing thehydraulic device to the roll by actuating fixing means on the roll end;d) loosening said lock ring from the thrust ring; e) opening of a chockend plate, releasing it from a flange; f) pressurising the hydraulicdevice by means of an actuator, thus exerting an axial force and forcingsaid thrust ring away from said thrust bearing, freeing the chock andthe oil-film bearing from the pressure on said roll neck; g) detachingsaid hydraulic device and said thrust ring from said roll end; and i)extracting, in the following order from the neck of the roll: a thrustbearing, a spacer ring, a tapered sleeve, and a bushing.